E8 is a communication fault between the control boards. Now theres 4 boards in there one at the back and the other 3 under the hob top.
What you need to do is make sure the power is turned off.
Open the top oven door and remove the screws under the front of the hob on the underside. There should be about 4 screws.
Once they are out you can then lift the hob up at the front.
From there you will see 2 control boards at the front one for the hob and the other for the oven.
On there is a yellow wiring harness connecting the boards together.
Unplug each end one at a time and give the ends a gentel squees and refit it.
Do this to all ends of the yellow wiring harness.
Then refit the hob and retry it and see how it goes. Fingers crossed it may be a loose connection on there and that gets it going.
But if not then its an electronic fault. Now im afraid it can be either one of the 4 boards in there. Theres no way to test them which makes this fault an absolute nightmare of a job.
As we order all boards and just fit which ever it is.
To be honest its either the main board at the back or the hob board under the glass hob towards the back.
But try the wiring first as sometimes doing that can clear the error code.
If you need anymore info just get back to me.